Press brakes



F. R. SAVORY June 13, 1967 PRESS BRAKES 5 Sheets-Sheet 1 Filed July 30,1964 Mil/1, 159M 3 5 F. R. SAVORY June 13, 1967 PRES S BRAKE S 5Sheets-Sheet 5 Filed July 30, 1964 W Z w MA, iwwz WW United StatesPatent 3,324,704 PRESS BRAKES Frederick Ralph Savory,Sutton-in-Ashfield, Nottinghamshire, England, assignor to SteelConstruction & Engineering Co. (Notts) Limited Filed July 3!), 1964,Ser. No. 386,225 Claims priority, application Great Britain, Aug. 9,1963, 31,460/63 2 Claims. (Cl. 72-453) This invention relates to pressbrakes, and more particularly to press brakes for bending sheet metalinto box sections.

When forming a box section from sheet metal one of the tool-carryingbeams (usually the movable one) of a press brake extends within the boxsection to form rightangle or other angle bends, radiused corners orcurved bends, and lies between the closing edges of the sheet metal asthe final bend is formed. To remove the formed box section from thepress brake the closing edges of the sheet metal must remainsufiiciently separated to permit withdrawal of the beam relatively fromthe formed box section, the closing edges of the box section beingbrought adjacent each other, and welded or otherwise secured together,if desired, after removal from the press brake. The bringing together ofthe closing edges may be diflicult to achieve, particularly with heavyguage metal, and may result in a permanent stressing of the metal whenthe closing edges are secured together. In addition, the stroke of themovable tool-carrying beam of a press brake must be considerable topermit withdrawal, often needing to be greater than the largestcross-sectional dimension of a box section to be formed, with the resultthat the press brake has a dimension in the direction of movement of themovable beam that is inordinately large as compared with the actualbending portion of the working stroke and a consequently slow cycle ofoperation.

It has been known to provide a press brake with a completely removableguide frame and drive connection for one end of one of the tool-carryingbeams (again, usually the movable one) so that a box section may beremoved endwise after removal of the guide frame and drive connections,but the improvement gained in enabling the formation of complete boxsections and in shortening the stroke has been greatly--if notcompletelyofiset by the time and labour involved in removing andreplacing the guide frame and drive connection.

According to the present invention, a press brake comprises a fixedtool-carrying beam, a movable tool-carrying beam, a pair of hydraulicrams connected one between each adjacent pair of ends of thetool-carrying beams, and means for supplying hydraulic fluid underpressure to the rams, the connection of one of the hydraulic ramsbetween the tool-carrying beams including a link pivotally connected atone end to one of the tool-carrying beams and pivotally connected at theother end to the hydraulic ram, that ram being carried by the othertool-carrying beam and one of the pivotal connections of the link beingremovable. Withdrawal of the removable pivotal connection breaks theconnection between the beams, at that end, and the link can be swungabout its other pivotal connection to permit endwise removal of a boxsection formed around one of the tool-carrying beams.

Means is preferably provided on the fixed tool-carrying beam adjacentthe other hydraulic ram (i.e., the one without the pivotal link) tosupport the movable tool-carrying beam in cantilever condition when theremovable pivotal connection of the pivotal link is withdrawn and avoidimposing any bending moment on that ram. Thus a cross-bar may be carriedby pillars on the fixed tool-carrying beam and span the edge of themovable beam opposite to the tool-carrying edge; the connection betweenthe beams including the ram without the pivotal link preferably alsoincludes a single pivot permitting limited swinging of the movable beamin its own plane, so that the ram cannot take any bending moment whenthe movable beam is in cantilever conditionthe pivotal connection beingremovable for maintenance purposes only. The pivotal link may beprovided with a removable locking pin enabling the movable beam to besecured parallel to the fixed beam.

The pivotal link is preferably a double-plate link, with one plate oneach side of the beam to which the link is pivoted, so that the workingload will not impose a bending moment on the link and/ or the rams.

The removable pivotal connection preferably comprises a taper pin, sothat any play, e.g., due to wear, can be taken up, the taper pin havinga screwed stern extending axially from its smaller end for engagement bya nut, which is preferably captive.

A preferred embodiment of the invention, and a slight modification, willnow be described by way of example only and with reference to theaccompanying drawings, in which FIGURE 1 is a front elevation of thepress brake, ready for performing bending operations;

FIGURES 2 and 3 are elevations of the right-hand and left-hand endsrespectively of FIGURE 1;

FIGURE 4 corresponds to the right-hand end of FIG- URE 1, but shows thepress ready for removal of a completed box section (not shown);

FIGURE 5 corresponds to the upper left-hand end of FIGURE 1, but shows apress brake provided with cropping and notching tools; and

FIGURE 6 is an elevation of the left-hand end of FIG- URE 5, partly insection on the line VI--VI in that figure.

Referring to FIGURES 1 to 3, a fixed beam 10 forms the upper part of aframe below a movable beam 11, with hydraulic ram cylinders 12A, 12Bsecured to the ends of the frame with their piston rods 13A, 13Bextending upwardly for connection to the movable beam, one connectionconsisting of a split collar 14 a lock-nut 15 permitting limitedpivoting of the movable beam, and the other connection consisting of adouble-plate link 16 with one plate 17 on each side of the movable beamand a block 18 screwed on the piston rod 13A, the link being connectedto the block by a non-removable pivot pin 19 and to the beam by aremovable tapered pivot pin 20 with a lock-nut 21 held captive to thelink by a split collar 22 engaging a neck in the nut and bolted to thelink.

The block 18 has shoulders 23 extending over the thickness of the linkplates 17, and the sides of the shoulders and the lower ends of the linkplates are sandwiched between guides 24 with bearings pads 25 which donot extend into the gap between the beams. The pivot pin 19 between theblock 18 and the link 16 is confined by the guides 24. The cylinder 12Ais bolted to the underside of a circular plate 26 (with a radial slot27) Welded across the bottom edges of the guides 24 and of an upperframe plate 28, which is welded to a vertical longitudinally-extendingweb plate 29 of the fixed beam 10, and flanked by a pair of spacedleg-forming lower frame plates 3% which are welded edge-to-edge to theupper frame plate. The piston rod 13A extends below the piston into asecondary cylinder 31 of smaller diameter, and there serves as a piston(as well as a guide) for effecting the return stroke (i.e., lifting) ofthe movable beam 11, as will be described presently.

At the other end of the press brake the other rain cylinder 12B isbolted to the underside of a similar circular slotted plate 26, but theguides 24 are replaced by a pair of gussets 32 supporting an extension10X of the fixed beam beyond an end frame otherwise similar to thefirst.

3 The piston rod 13B is similar to that of the first cylinder unit, butin the second cylinder unit the extension serves as a guide only. Thepiston rod 13B screws into a coupling 33 on the lower end 34 of asecondary rod 13X which passes through a hole 35 in the extension 10X ofthe fixed beam 10 and a steady 36 bolted on that beam, the upper end ofthe secondary rod having an upwardlyfacing shoulder 37 to support thesplit collar 14 a reduced shank 38 passing with appreciable clearancethrough a hole 39 in an upright boss 40 in the movable beam 11, and ascrewed end 41 for the lock-nut 15. The lock-nut has a part-sphericalconvex bottom surface 42 mating with a corresponding concave top surface43 of the boss in the movable beam and the boss has a part-cylindricalconvex bottom surface 44 of a radius exceeding the radius of the topsurface by the depth of the boss and extending transversely of the beam,the split collar 14 having a corresponding concave upper surface 45 tomate with the bottom of the boss but interrupted by slots 46 for a pairof keys 47 which also engage slots 48 in the bottom of the boss, toprevent lateral displacement whilst permitting pivoting of the movablebeam 11 in a vertical plane.

The movable beam has an extension 11X overhanging the extension 10X ofthe fixed beam 10 and normally bridged by a cross-bar 49 with ascrew-down stop 50 bolted to the tops of two pillars 51 the lower endsof which screw into holes in the extension of the fixed beam. The usualgrooves 52 and rebate 53 are provided along the length of the beams forattachment of press tools 54, 55.

The feet of the leg-forming plates 30 are connected in pairslongitudinally by side channel members 56, which are connected at anumber of intermediate positions by transverse channel members 57providing support for a motor 58 and pump 59 for the rams and an oilreservoir 60, the side channels being welded to the leg-forming platesand the transverse channels being welded to the side channels, and themotor and the reservoir being bolted tothe channels.

The cylinders 12A, 12B are operated in tandem for the working stroke,i.e., oil is supplied under pressure by the pump 59 to the upper end ofthe cylinder 12B the lower end of which is connected to the upper end ofthe cylinder 12A, pressurising of the upper end of the cylinder 12Abeing effected by transfer of oil from the lower end of the cylinder1213. The smaller secondary cylinder 31 of the cylinder unit 12A onlyeffects rapid return of the movable beam under the same pressure as forthe working stroke, oil from the upper end of the cylinder 12A beingtransferred back to the lower end of the cylinder 12B.

Withdrawal of the tapered pivot pin 20 breaks the connection between thebeams 10, 11, at that end, and the link 16 can be swung about its otherpivot pin 19 (as indicated by FIGURE 4) to permit endwise removal of abox section (not shown) formed around the beam 11, the cylinder 12Bbeing utilised to urge the beam 11 upwards to bring its extension 11X upagainst the screwdown stop 50 and hold the beam 11 in cantilevercondition.

Tapped holes 61 (FIGURE 1 only) in the movable beam permit the fixing ofa stiffening bar 62 (indicated in broken line) to one or both sides ofthe movable beam,

or of a guillotine blade (not shown) to one side in place of the presstool 55.

As shown by FIGURES 5 and 6, a modified extension 11Y of the movablebeam 11 has a rebated aperture 63, into which is bolted a cropping tool64 for co-operation with a similar tool 65 carried by a bracket 66 whichis bolted to the extension 10X of the fixed beam 10 in place of thepillars 51 for the cross-bar 49, the cropping tools being providedwithcorresponding holes 67 of round-, square-, and F-section for thecropping of round or square bars (as well as bars of other section whichwill fit the round and square holes) and of angle-, channeland T-section. A notching tool 68 is also secured to the extension 11Y forco-operation with a complementary tool 69 secured to the extension 10Xof the fixed beam. Punching dies (not shown) may be secured to theextensions 10X, 11Y in place of the notching tools 68, 69.

What I claim is:

1. A press brake comprising a fixed tool-carrying beam, a movabletool-carrying beam, a pair of hydraulic rams connected one between eachadjacent pair of ends of the tool-carrying beams, and means forsupplying hydraulic fluid under pressure to the rams, the connection ofone of the hydraulic rams between the tool-carrying beams including alink pivotally connected at one end to one of the tool-carrying beams,and pivotally connected at the other end to the hydraulic ram, that rambeing carried by the other tool-carrying beam, and one of the pivotalconnections of the link being removable, together with pillars on thefixed tool-carrying beam, a cross-bar carried by the pillars andspanning the edge of the movable beam opposite to the tool-carryingedge, and a single pivot in the connection without the pivotal link,permitting limited swinging of the movablebeam in its own plane.

2. A press brake comprising a fixed tool-carrying beam, a movabletool-carrying beam, a pair of hydraulic rams connected one between eachadjacent pair of ends of the tool-carrying beams, and means forsupplying hydraulic fluid under pressure to the rams, the connection ofone of the hydraulic rams between the tool-carrying beams including adouble-plate link pivotally connected at one end with one plate on eachside of one of the tool-carrying beams and pivotally connected at theother end with one plate on each side of the hydraulic ram, that rambeing carried by the other tool-carrying beam, and one of the pivotalconnections of the link comprising a removable taper pin having ascrewed stem extending axially from its smaller end for engagement by acaptive nut, together with pillars on the fixed tool-carrying beam, 2.cross-bar carried by the pillars and spanning the edge of the movablebeam opposite to the tool-carrying edge, and a single pivot in theconnection without the pivotal link, permitting limited swinging of themovable beam in its own plane.

References Cited UNITED STATES PATENTS 1,585,212 5/1926 Schranz 72455CHARLES W. LANHAM, Primary Examiner.

R. D. GREFE, Assistant Examiner.

1. A PRESS BRAKE COMPRISING A FIXED TOOL-CARRYING BEAM, A MOVABLETOOL-CARRYING BEAM, A PAIR OF HYDRAULIC RAMS CONNECTED ONE BETWEEN EACHADJACENT PAIR OF ENDS OF THE TOOL-CARRYING BEAMS, AND MEANS FORSUPPLYING HYDRAULIC FLUID UNDER PRESSURE TO THE RAMS, THE CONNECTION OFONE OF THE HYDRAULIC RAMS BETWEEN THE TOOL-CARRYING BEAMS INCLUDING ALINK PIVOTALLY CONNECTED AT ONE END TO ONE OF THE TOOL-CARRYING BEAMS,AND PIVOTALLY CONNECTED AT THE OTHER END TO THE HYDRAULIC RAM, THAT RAMBEING CARRIED BY THE OTHER TOOL-CARRYING BEAM, AND ONE OF THE PIVOTALCONNECTIONS OF THE LINK BEING REMOVABLE, TOGETHER WITH PILLARS ON THEFIXED TOOL-CARRYING BEAM A CROSS-BAR CARRIED BY THE PILLARS AND SPANNINGTHE EDGE OF THE MOVABLE BEAM OPPOSITE TO THE TOOL-CARRYING EDGE, AND ASINGLE PIVOT IN THE CONNECTION WITHOUT THE PIVOTAL LINK, PERMITTINGLIMITED SWINGING OF THE MOVABLE BEAM IN ITS OWN PLANE.